Slack is a cloud-based software with U.S.-based servers. It’s not possible to self-host sensitive company data, which some companies consider a sig­ni­fic­ant dis­ad­vant­age. It’s also a major reason why companies search for Slack al­tern­at­ives.

What can Slack do?

Before re­search­ing Slack al­tern­at­ives, it’s a good idea to look into what makes Slack so popular and which features its com­pet­it­ors have to compete with. The com­mu­nic­a­tion tool is primarily a stream­lined solution for companies that don’t want to host project col­lab­or­a­tion and document sharing them­selves. All you need to provide is in­form­a­tion about your industry, the number of employees and your role at your company. Slack then uses this in­form­a­tion to optimise its user interface. Once that’s complete, you need to select your domain based on your company name.

The core of Slack is the channel. Chatrooms can be created for any important projects or teams. Team leaders can simply add people to a specific channel and edit the access per­mis­sions ac­cord­ingly. The simple and intuitive user ex­per­i­ence makes Slack a very popular choice.

An overview of al­tern­at­ives to Slack

Type Cost Suitable for Features
Spike Email tool and comĀ­muĀ­nicĀ­aĀ­tion platform Free, subĀ­scripĀ­tion for proĀ­fesĀ­sionĀ­al users Startups to large companies InĀ­novĀ­atĀ­ive email presentĀ­aĀ­tion
Fleep Cloud-based comĀ­muĀ­nicĀ­aĀ­tion platform SubĀ­scripĀ­tion with free trial period Self-employed, startups, SMEs Chat with email contacts in the tool
Rocket.Chat Open-source comĀ­muĀ­nicĀ­aĀ­tion software Freeware, subĀ­scripĀ­tion with premium features SMEs, large companies Link preview, B2C live chat for your website
MatĀ­terĀ­most Self-hosted, open-source team comĀ­muĀ­nicĀ­aĀ­tion software Freeware, subĀ­scripĀ­tion with premium features Teams, large enĀ­terĀ­prises with strict security standards Multi-platform support
Microsoft Teams Cloud-based team comĀ­muĀ­nicĀ­aĀ­tion software Free, subĀ­scripĀ­tion with premium features Medium to large orĀ­ganĀ­isaĀ­tions Full Microsoft Office 365 inĀ­tegĀ­raĀ­tion

What are the best Slack al­tern­at­ives and what can they do?

Despite the positive aspects of the popular chat program, data pro­tec­tion and security remain important arguments against using it. In this section, we’ll introduce you to the best Slack al­tern­at­ives, some of which are free of charge, while others come at a cost. Which al­tern­at­ive will appeal the most to you depends on what’s most important for your company’s internal com­mu­nic­a­tion.

Spike, the in­nov­at­ive Slack al­tern­at­ive

Spike is re­de­fin­ing the way teams com­mu­nic­ate and col­lab­or­ate. Spike is a team chat solution that provides unified com­mu­nic­a­tion and col­lab­or­a­tion for busi­nesses of all sizes. With Spike, you get access to fully hosted messaging, chat, and email cap­ab­il­it­ies that enable seamless com­mu­nic­a­tion within internal teams and with external stake­hold­ers, even if they aren’t Spike users. In contrast to Slack, there are no ad­di­tion­al add-ons or plugins required for com­mu­nic­a­tion.

Another notable feature Spike provides is Super Search, which helps you locate any keyword, phrase, note, document or file that you have sent from or received in your inbox. You can easily see all files in every thread at a glance (even in group chats), making it super simple to find anything and everything you’re searching for. Spike’s latest addition, Magic AI, in­tro­duces an in­nov­at­ive AI-driven com­mu­nic­a­tion assistant that redefines business messaging. By combining human cre­ativ­ity with ar­ti­fi­cial in­tel­li­gence, Magic AI boosts pro­ductiv­ity, stream­lines daily workflows and saves valuable time.

Image: Screenshot of the Spike website
Spike website / Source: https://www.spikenow.com/email-app/

Notably, Spike stands out as an al­tern­at­ive to popular com­mu­nic­a­tion tools like Slack. It seam­lessly in­teg­rates work team chat, email, video and audio meetings, advanced AI tools, and col­lab­or­at­ive documents, promoting an efficient and pro­duct­ive working en­vir­on­ment. You have the flex­ib­il­ity to use your own email domain or purchase a custom domain from Spike, ensuring secure, reliable and archiv­able email and messaging. Spike supports web-based clients, mobile apps and desktop ap­plic­a­tions for stream­lined col­lab­or­a­tion.

Spike’s pricing structure offers ex­cep­tion­al value, with its Team package priced at $6 (just under £5) per member/month. This package includes a custom email domain, unlimited search history, 100 GB of storage space and the ability to upload large files up to 100 MB. Ad­di­tion­ally, it provides priority support for timely as­sist­ance. Spike’s pricing balances func­tion­al­ity and af­ford­ab­il­ity, making it an at­tract­ive choice for busi­nesses of all sizes.

Pros Cons
Video and voice calls InĀ­tegĀ­raĀ­tion with other apps not possible
Many features included in the free version
Advanced search function

Fleep, the European cloud

Fleep is a cloud-based com­mu­nic­a­tion platform. The startup behind the software is based in Estonia and the team of de­velopers already have relevant ex­per­i­ence working on the renowned Microsoft service Skype. The cloud server has an Amazon EC2 data center in Dublin. The ap­plic­a­tion began in 2013 and now functions with Mac, Linux and Windows operating systems on both web browser and desktop. Users can access the messenger service on the go with the iOS and Android app.

The free version, which can be used for two weeks, is free for everyone and comes with a large feature package. The business version, on the other hand, allows you to set up an ad­min­is­trat­or account which you can use to create chat rooms and invite users. The platform allows you to conduct con­ver­sa­tions and chats with external teams and companies, and addresses without a Fleep account can write directly in a chat window and will receive your messages as emails. In this way, Fleep tries to shorten com­mu­nic­a­tion channels without denying companies their familiar struc­tures.

Image: Screenshot of the Fleep homepage
Fleep website / Source: https://fleep.io/features

In the Business as well as the En­ter­prise version, you’re allowed an unlimited number of users and con­ver­sa­tions. Users can find all archived projects or team chats using the search function. Files can be uploaded to a con­ver­sa­tion with one simple click and tasks can be easily set and managed. Ad­di­tion­ally, marked messages as well as file uploads can be found in the side bar.

You can integrate unlimited apps. In addition to the usual cloud services, email and project man­age­ment tools, there’s also Whereby. This plugin sup­ple­ments the Slack al­tern­at­ive’s text-based chat system with audio and video call functions. You can use the Fleep API to integrate larger ap­plic­a­tions or custom apps. Each user has 100 GB of storage space at their disposal. Further features include:

  • Account, chat and team man­age­ment as ad­min­is­trat­or
  • Company name in profile
  • Company logo for all sub-users in the tool
Pros Cons
Own company logo and name in tool Limited file storage
Voice and video call inĀ­tegĀ­raĀ­tion Self-hosting not possible
Cloud server in the EU

Rocket.Chat, open-source software gaining on Slack’s heels

Rocket.Chat is a free open source al­tern­at­ive to Slack. The messenger software arrived on the market in 2016 and records some of the largest mem­ber­ship numbers within the GitHub developer community. In the wake of Slack’s ground­break­ing success, many pro­gram­mers felt the need to develop a better open-source version.

The program stands out amongst the al­tern­at­ives to Slack because it’s not only free of charge, but, thanks to open-source code, it is also easily cus­tom­is­able for de­velopers. For large companies that need tech support, there are also fee-based versions. In the basic version, Rocket.Chat only provides the ap­plic­a­tion, with the hosting done in­di­vidu­ally by each team. Users download the server, where sensitive data can be stored. For those that do in fact want a host, Rocket.Chat offers a free, scalable cloud service.

Image: Screenshot of the Rocket.Chat website
Rocket.Chat website / Source: https://www.rocket.chat/

Rocket.Chat offers the normal messenger features that every good Slack al­tern­at­ive should provide. There are team and project-related chats as well as private messages. Private channels, as seen above, are closed channels with extra encrypted content that’s not archived. Ad­di­tion­ally, Rocket.Chat adapts to different user types. The in-house company com­mu­nic­a­tion functions just as seam­lessly as Rocket.Chat’s in­teg­rated B2C live chat on your website. You can add an unlimited number of users, guests and channels. All messages are end-to-end encrypted. Two-factor au­then­tic­a­tion for file sharing provides ad­di­tion­al security.

The developer team is con­stantly working on the Rocket.Chat code, which enabled them to implement the API into the core software. You can use Hubot and Webhooks to integrate the existing tools and other Rocket.Chat bots. The community re­com­mends Jitsi Video Bridge to stabilise the existing video chat and connect chat partners that are geo­graph­ic­ally dispersed. Further in­teg­ra­tions include:

  • Google Calendar
  • Dead­SimpleScreen­Shar­ing
  • Azure Alerts
  • BitBucket
  • WhatsApp
  • DropBox
  • Jira
  • Trello
  • GitHub and GitLab
  • Zapier

Rocket.Chat is ahead of Slack in terms of voice and video call features. During a meeting, chat par­ti­cipants can easily join the con­ver­sa­tion and get access to the screen sharing option. The typical con­ver­sa­tion chaos that comes about with long chats is organised by Threads and Hubot – though this is not as developed as the Slack model, the slackbot.

Pros Cons
Supports 50 languages with automatic real-time transĀ­laĀ­tion Priority support with monthly costs
Self-hosting possible
Easy to install on existing inĀ­fraĀ­strucĀ­ture

Mat­ter­most, your data remains safe on your own server

Mat­ter­most is another open-source solution for internal com­mu­nic­a­tion. This platform can be hosted on your own server or in a private cloud behind your firewall. This way, you retain full control over sensitive data. The Slack al­tern­at­ive can be easily in­teg­rated into your existing on-site in­fra­struc­ture. If you’re already hosting your processes in a public cloud, Mat­ter­most can be easily added to your en­vir­on­ment. Users praise the tool’s hassle-free scalab­il­ity. The number of users is limited only by the server being used.

Mat­ter­most is another open-source Slack com­pet­it­or that wants to do things better. The company spe­cial­ises in secure company com­mu­nic­a­tion. Those that need to comply with strict security and com­pli­ance standards will often find it easier to keep all data on their own server. To do this, select your server during in­stall­a­tion and specify the domain. Then specify whether the program is allowed to send push messages, check spelling or auto­mat­ic­ally start every time it boots.

Image: Screenshot of the Mattermost website
Mat­ter­most website / Source: https://mat­ter­most.com/

The messenger app has a free team edition and two fee-based versions. The Pro­fes­sion­al package is optimised for teams and de­part­ments that want more control over their IT in­fra­struc­ture. Encrypted push no­ti­fic­a­tions and AACP ensure high security standards. There is a fixed monthly price for the service. The En­ter­prise version comes with extra com­pli­ance and security features and includes:

  • Extended com­pli­ance support
  • Ad­di­tion­al au­then­tic­a­tion
  • Extended support for your data center
  • Company analysis

The basic version offers a practical messenger for private clouds and includes all basic functions that come in the En­ter­prise package. Even with the free version, users can benefit from con­tinu­ous im­prove­ment updates.

In the program, you can create teams for cor­res­pond­ing users and each channel allows you to chat about a specific topic. The thread structure clears up long con­ver­sa­tions. In addition to dis­play­ing the message you are looking for, the search function also displays the con­ver­sa­tion context. The taskbar allows users to upload files and search archived documents. From within the chat, users can see when a con­fer­ence call is taking place and can join the call by accepting the in­vit­a­tion. A calendar entry will be created for this be­fore­hand. In addition to private messages, the VoIP tool enables instant messaging calls and video con­fer­ences.

Tip

Use the community to request feature en­hance­ments. There are plenty of de­velopers in the community that are happy to help.

Unlimited in­teg­ra­tions can be added if required. However, in terms of usability, Slack has the edge with a simple one-click in­stall­a­tion process, whereas Mat­ter­most must be installed manually. While Slack limits bots and apps to 10, Mat­ter­most is unlimited. Also, Slack limits the number of archived messages to 10,000, whereas Mat­ter­most places no limit on the amount of messages that can be archived. The program is available in a web version, as a desktop ap­plic­a­tion and as a mobile app.

Pros Cons
InĀ­diĀ­viduĀ­al security standards with your own server No 1-click app inĀ­tegĀ­raĀ­tion as with Slack
MulĀ­tiĀ­linĀ­gual user interface
Open-source code for maximum adĀ­aptĀ­abĀ­ilĀ­ity

Microsoft Teams, good in­teg­ra­tion for Office 365 users

Microsoft Teams is a messenger tool that is part of the Microsoft 365 Business suite. When Qi Lu, an employee in Microsoft’s ap­plic­a­tions and services de­part­ment wanted to buy Slack, Microsoft founder Bill Gates had other ideas. Instead, he wanted to develop a new version of Skype for Business as an al­tern­at­ive to Slack. Microsoft announced the project at the end of 2016. In turn, Slack in­tens­i­fied its co­oper­a­tion with Google.

Following offers from the likes of Yammer and Skype for Business, Microsoft developed the Slack al­tern­at­ive Teams that promised to challenge the com­pet­i­tion. While Yammer is best suited to larger companies, Teams is best for medium-sized to large companies. You can choose to use Teams free of charge (with various re­stric­tions) or with a paid sub­scrip­tion.

Image: Screenshot of the Microsoft Teams website
Microsoft Teams website / Source: https://www.microsoft.com/en-gb/microsoft-teams/group-chat-software/

While much criticism has been voiced about Microsoft’s updates, there is little to fault with Messenger. The software has all the essential features such as chat and instant messages. The HD video calls can host up to 300 people. With guest access, you can also invite people outside of your company to work together in teams. The Outlook calendar in­teg­ra­tion was lacking during its initial phases but has since been added. Here, teams receive no­ti­fic­a­tions about upcoming meetings that have been arranged via Microsoft Teams.

Files can be shared in chats or instant messages via the OneDrive cloud, and Teams encrypts the documents end to end and protects users’ identity with multi-factor au­then­tic­a­tion. When sharing files on one channel, the program places them in the shared Share­Point folder for all team members. In addition, voice call functions like meetings and VoIP are included. The software also supports calls to phones. The program also includes a task manager to improve workflow op­tim­isa­tion.

Chatbots can be added via the app store. Simply click on the Apps button and choose the tab Bots. The bots answer questions, provide on-the-spot as­sist­ance and take care of updates.

Pros Cons
Stable inĀ­tegĀ­raĀ­tion with all Office programs Lack of privacy: Microsoft scans files for OneDrive
Office 365 security standards and proĀ­fesĀ­sionĀ­al-level cerĀ­tiĀ­ficĀ­ates
Clear, cusĀ­tomĀ­isĀ­able menu
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